We investigated the effects of season and weather on the winter roosting behavior of American Crows (Corvus brachyrhynchos) in central Iowa from January through March 2006. The peak number of birds recorded at a roost in Ames, Story County was 9,000+ in early February, and the number of individuals entering the roost decreased through February and March. Crows tended to enter the roost later in the day as winter neared completion. High wind speed and low light intensity caused individual to enter the roost earlier in the day. Temperature did not affect arrival time of crows. Wind speed, light intensity, and temperature did not significantly affect total number of individuals entering the roost (P > 0.05). However, all three factors were negatively correlated to total number of birds on the roost (-0.20, -0.25, and -0.18 respectively). This research improves our understanding of the roost dynamics of an abundant urban wildlife species, which may eventually be used to manage interactions between humans and wildlife in an urban setting.